Case IH 19595 – DCU (Dosing Control Unit): CAN receive frame EEC1 (Driver demand, eng speed, eng torque) | SAE J1939 Check for CAN receive signal : (Engine torque not in range) | P0600 Serial Communication Link

There is a communication anomaly on the SAE J1939 CAN bus network. The Dosing Control Unit (DCU) is successfully receiving the EEC1 (Electronic Engine Controller 1) data frame from the Engine Control Unit (ECU), but the specific data parameter for 'Engine Torque' is outside of the valid or expected range. This triggers a P0600 serial communication link error.

• Tier 4a
• Magnum 235
• Magnum 260
• Magnum 290
• Magnum 315
• Magnum 340
• Magnum 370
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 550
• Steiger 600
• Puma Series

1. 1

   Check system voltage and load-test the battery, as low voltage is a primary cause of CAN communication errors

2. 2

   Check for primary engine faults using the Electronic Service Tool (EST) to see if the Engine ECU is broadcasting invalid values due to failed engine sensors

3. 3

   Inspect the SAE J1939 CAN bus wiring harness between the Engine ECU and the DCU for chafing, shorts to ground, or open circuits

4. 4

   Inspect the wiring harness connectors at both the DCU and the Engine ECU for moisture intrusion, corrosion, or bent pins

1. 1

   Scan the System

   Connect the CNH Electronic Service Tool (EST) and pull all active and stored fault codes from both the Engine ECU and the DCU.

2. 2

   Address Root Engine Codes

   If the Engine ECU has active codes related to engine performance or sensors, diagnose and repair those first. Fixing the engine sensor issue will restore the correct torque value broadcast to the DCU.

3. 3

   Test the Battery

   If no other codes are present, test the battery and charging system. Clean the battery terminals and chassis ground connections. Replace the battery if it fails a load test.

4. 4

   Test the CAN Network

   With the batteries disconnected, use a multimeter to measure the resistance across the CAN bus lines at the DCU connector. A healthy CAN network should read approximately 60 ohms.

5. 5

   Repair Wiring

   If resistance is out of spec (e.g., 120 ohms indicates a broken wire or missing terminating resistor), trace the harness between the DCU and Engine ECU and repair the damaged section.

6. 6

   Module Replacement (Last Resort)

   If the wiring is perfectly intact, voltage is correct, and no other engine codes exist, the DCU may have an internal failure. Note: Replacing the DCU requires CNH dealer software to install the module and flash the correct parameters.

7. 7

   Clear and Test

   Clear all fault codes using the EST and test drive the tractor under load to verify the EEC1 CAN frame is communicating properly.